점토-시멘트 혼합토의 강도특성에 영향을 미치는 배합조건에 관한 연구

Abstract

Deep cement mixing method (DCM) has been frequently employed to increase a bearing capacity and to reduce a settlement of soft foundation soils. The magnitude of strength increase of soil stabilized with the deep cement mixing method is influenced by several factors because the basic mechanism of strength increase is closely related to the chemical reaction between soil and cement. The factors can be divided into four categories such as characteristics of binder, soil conditions, mixing conditions, and curing conditions. The objective of this study is to investigate the effect of various factors on the strength characteristics of clay-cement specimens fabricated in the laboratory. Factors evaluated in the study include sand and water content in the base clay, mixing method, quantity of cement, degree of mixing, mixing time, mixing velocity, quantity of sand, and curing time. The unconfined compressive strengths of clay-cement specimens fabricated with a wet mixing method were appeared to be smaller than those fabricated with a dry mixing method. The unconfined compressive strengths of clay-cement specimens tended to decrease as the water-cement ratio was increased. The amount of sand and the water content in the base clay has significantly affected the unconfined compressive strength of clay-cement specimens. In addition, the rotation speed of mixing blades and mixing time has also a considerable effect on the strength of clay-cement specimens. The water-clay to cement ratio showed a better correlation with a unconfined compressive strength of clay-cement specimens compared to the water-cement ratio used in concrete industry.